Preheat oven to 325°F (160°C). Line the bottom of a 9-inch springform pan with parchment paper and grease the sides.
Mix graham cracker crumbs, sugar, and melted butter until crumbly. Press into the pan and bake for 8-10 minutes until golden. Let cool.
Beat cream cheese and sugar until smooth. Add vanilla, lemon zest, and sour cream, mixing until combined. Add eggs one at a time, mixing gently. Stir in flour and pour over the cooled crust.
Place pan on a baking sheet. Bake for 50-60 minutes until edges set but center is jiggly. Turn off oven, crack the door, and let cool for 1 hour.
In a saucepan, cook sliced strawberries and sugar over medium heat until softened. Stir in cornstarch slurry and cook until thickened. Let cool.
Combine flour, brown sugar, oats, and cinnamon. Cut in cold butter until crumbly. Spread on a baking sheet and bake at 350°F (175°C) for 8-10 minutes until golden. Let cool.
Spread strawberry sauce over the cheesecake, then sprinkle with crunch topping. Refrigerate for 4-6 hours or overnight to set.